The present invention relates generally to communication networks, and more specifically, to dynamic path protection in an optical network and integration with link protection schemes in an IP network.
The rapid growth of the Internet and the widespread deployment of networks built around the Internet Protocol suite are creating a demand for new capabilities in IP (Internet Protocol) networks. MultiProtocol Label Switching (MPLS) provides a number of powerful capabilities such as traffic engineering, etc. As with IP routers, MPLS nodes use a routing protocol such as OSPF or IS-IS to calculate network paths and establish reachability. MPLS is an IETF (Internet Engineering Task Force) initiative that integrates Layer 2 information about network links (bandwidth, latency, utilization) into Layer 3 (IP) within a particular autonomous system in order to simplify and improve IP packet exchange. MPLS-TE provides network operators a great deal of flexibility to divert and route traffic around link failures, congestion, and bottlenecks.
Generalized MPLS (GMPLS) extends MPLS-TE to provide a control plane (signaling and routing) for devices that switch in domains such as packet, time, wavelength, and fiber. This common control plane simplifies network operation and management by automating end-to-end provisioning of connections, managing network resources, and providing a level of QoS that is expected in new applications. GMPLS extends the suite of IP-based protocols that manage and control the establishment and release of label switched paths (LSPs) that traverse any combination of packet, TDM, and optical networks.
Protection of switched LSPs is important, and more particularly, with respect to GMPLS nodes connected in a general topology and under tight time constraints. One requirement for protection in IP and optical networks is to avoid or reduce the effects of failures in optical network in the IP topology/traffic. More specifically, if a link that is part of an end-to-end GMPLS connection fails, it is preferred that this failure not result in a failure of routing adjacency (e.g., IGP adjacency). This is because local failures can be addressed much more quickly and efficiently inside the optical network. Also, IP convergence is slower than any technique that optical networks can provide and there is a need for service isolation. Thus, service providers in general would like the GMPLS network to handle failures in the optical networks such that they do not affect routing adjacencies.
Conventional approaches for protection against failures in optical networks in the IP topology/traffic have the drawback that a failure in doing local restoration results in failure of routing adjacencies.
There is, therefore, a need for a system and method for handling failures in an optical network such that the failure does not affect routing adjacencies.